Binding of HIV‐2 envelope glycoprotein to CD8 molecules and related chemokine production

We recently found that human immunodeficiency virus (HIV)‐2 envelope glycoprotein, but not that of HIV‐1, could bind to CD4 and CD8 molecules on T cells, and that the binding site of HIV‐2 envelope glycoprotein was located on the α‐chain (but not the β‐chain) of CD8. This study showed that the binding of HIV‐2 envelope glycoprotein could induce phosphorylation of protein tyrosine kinase p56lck in CD8+ T cells. We also found that production of β‐chemokines in response to HIV‐2 envelope glycoprotein was significantly higher than that in response to HIV‐1 envelope glycoprotein, and that CD8+ T cells were the main source of β‐chemokines production among the T‐cell population. These findings indicate the possibility that the binding of envelope glycoprotein to CD8 molecules are related to signal transduction into CD8+ T cells and the resultant β‐chemokine production in HIV‐2 infection. Our results may help to explain the differences in disease manifestations between HIV‐1 and HIV‐2, including the lower virulence of HIV‐2 and the longer survival of HIV‐2‐infected individuals.